Juuling, or using a type of electronic cigarette that looks like the USB sticks used to save electronic documents and other data, is growing in popularity and racking up revenue. It's also vexing parents and teachers who want to discourage young people from picking up the habit. As the 2018-2019 academic year gets underway, teachers and principals are concerned that the popularity will continue to grow. With Juul's discreet and odorless nature, teachers have a hard time catching students. Additionally, experts say that the brand's many flavors - such as mango and mint - make it an attractive product for younger users.